Abstract: Considering the properties of reservoir sand and the characteristics of perforation tests, a 3-dimensional particle flow code (PFC^3D) model is established based on the cylindrical coordinate system from geo-mechanics perspective. Under the cylindrical coordinate system, the fluid-solid coupling theory considering pressure gradient force and drag force and the geometrical theory are adopted to study the change of the geometric model considering sand production in oil wellbore. Comparison between the numerical model and the analytical model indicates that the fluid flow should not be neglected for analysis of sand production, and the stress distribution is in coincidence for the above two methods, which verifies the feasibility and applicability of the proposed numerical model. In addition, under the given conditions, the results including the stress distribution, bonded particles, particle displacement and coupling force on the single particle indicate that different divisions of fluid cells have minor influence on the numerical simulation, which verifies the convergence and stability of this numerical model. Therefore, the proposed model can be used to simulate the macro-micro mechanical characteristics of sand production, and it provides an important technique to better reveal the mechanism of sand production.